Electrical coupling switch



July 26, 1949. 1 2 2,477,387

ELECTRICAL COUPLING SWITCH Filed March 1, 1946 INVENTOR ERw/v MEST/TZ ATTORNEY.

Patented July 26, 1949 UNITED ELECTRICAL COUPLING SWITCH ErvinMestitz, Llandafi", Cardiff, South Wales Application March 1,1946, Serial No. 551,214

In Great Britain February 23, 1945 This invention relates to combined coupling switches and has for its object to provide a rotary switch on a coupling secured to a cable and suitable for connection to electric appliances such as pressing irons, kettles, toasters and the like. Whilst it has been known heretofore to provide switches on appliances and on Wall sockets a combined coupling switch according to this invention has the advantage that the same cable with the coupling switch can be used for a variety of appliances and that the switch is at a suitable distance from the hot appliance to which the coupling is connected. The rotary switch has no projecting press button and is not liable to be inadvertently operated.

An electrical coupling according to this inven tion therefore comprises terminals for cable connection, coupling contacts and a rotary switch connected between one of the said contacts and one of the said terminals, the terminals, contacts and switch being held in a common casing consisting of two shell shaped parts. The said shell shaped parts can be of identical outer surface, and an operating knob of the switch can be so engaged by the ends of the shell shaped parts that the knob is rotatably held by the said parts and cannot move in an axial direction.

Another object of the invention is to provide a spring between the operating knob of the switch and a rotatable switch contact in such manner that the spring serves for pressing the rotatable contact piece against its counter contact and also for ensuring a quick make and break action. The main body of the coupling can be torpedo shaped and the operating knob of the switch can be arranged at one end whilst the cable entry is at the other end of the torpedo shaped body.

More details will be apparent from the drawings which illustrate diagrammatically by way of example preferred embodiments of the invention.

Figure 1 shows one part of the casing of a coupling with the rotary switch and electrical connections arranged in it.

Figure 2 is a top view of the coupling showing the dividing line between the two parts of the casing.

Figures 3 and 4 show on a larger scale details of the switch construction.

Figure 3 is a section along the line AA viewed in the direction of the arrow a and shows the insulating support for the stationary counter contacts, whilst Figure 4 shows the movable contact piece and its connection to the operating knob.

The combined coupling switch comprises an elongated casing whose main portion l housing 2 Claims. (Cl. 20051) the rotary switch is of torpedo-, cigar-, or similar shape, a cylindrical projection 2 being provided to hold the coupling contacts l2, l3. The casing is subdivided into two shell like parts 3, 4 Whose surfaces are preferably of identical shape.

The casing can be made of any material which is known in the art for the casing of electrical apparatus, particularly insulating material, e. g. resinous moulding material, hard rubber, the material which is known under the trade-mark Mycalex and the like. The two parts 3, 4 of the casing are connected together by means of bolts reaching through holes 5, 6, or by screws reaching through holes in one part and engaging threaded inserts in the other part of the casing. The coupling contacts l2, I3 can be provided with shoulders M or the like to be gripped and held in position between the recessed faces 55 of the two parts 3, 4 when they are pressed against each other. Instead of pin contacts as shown in the drawing contacts of tubular or any other shape known in the art can be used. Apart from the said'recesses for the couplingcontacts the joining faces l5 of the parts 3, 4 can be plane as shown in the drawings or one of the faces can be provided with a groove and the other one with a projection, and gaskets or packings can be used for water tight joints.

The rotary switch is arranged in series with the contacts l3. The stationary contacts 23, 24 of the switch are respectively connected via an intermediary conducting member 2| to the coupling contact l3 and via a lug ID to one wire 20 of a two cored cable 16 whose other wire I!) is connected direct to the other coupling contact I2.

Both the lug l0 and the coupling contact I2 are provided with suitable terminals for cable connection. Undesirable stresses on these terminals are prevented by cable gripping means I! as is known in the art.

The stationary switch contacts 23, 24 are supported by a suitable insulating piece 25 which may be integral with the shell like part 3 of the casing and in which the fixing holes 5, li are provided. The stationary contacts, preferably of Phosphor bronze, are slightly concave and securely held in recesses 30 and slots 3| of the insulating piece 25 (Figure 3). Shallow recesses 32 similar in shape to the shallows of the stationary contacts 23, 24 are provided in the insulated piece 25 and positioned at right angles to the cylindrical shallows in the said contacts 23, 24.

The movable contact bridge is formed by a bar or rod 26 e. g. of Phosphor bronze secured to a. spindle 21 which is guided in a hole 33 of the inresinous moulding material.

genes? sulating'piece 25 (Figure 3) and in a hole 34 of an operating knob 28 of insulating materiai, e. g. a A helical spring 29 and may reach into an axial hole of the knob. The rotatable-part of the switcheand particularly the knob 28 is supported by the edges of the shell like parts of the casing which form a circular bearing engaging a groove 35 of the knob 28..

It will be understood that the spring 29 thus serves for pressing the switching bar against its stationary counter contacts 23, 243 and also for moving .it abruptly to ensure aouick make and break action. If the knob is turned in a clockwise direction the switching bar 26 does not move with the knob until the torsional force of the spring 29 moreomes its axial pressurethen the switching lifted out @oi the shallows of the insulator and moves abruptly into the shallows of the counter contacts. The elastic power accumulated in the spring .39 whilst the knob 23 is turned betore the bar 25 is moved accelerates the movement of the said switching bar when it starts moving and thus affords the quick make and :break action. The

1 magnitude-of the torsional power and of the-pres- V ssm ebetween the co-operatingcontacts wean be :ad-

justed by the prletension of the spring.

The operating knob 28 and the casing can be marked at3li, 3! and 38 to indicate the on and oil positions of the switch.

Variations are possible without departure from the invention. The insulating piece supporting the stationary switch contacts need not be intogral with thecasing and may iform .a separate ,piece which is held inposition between the two shell like parts of the casing. The cable may be sheathed with rubben artificial rubber :and the like and the sheathing may he Joined to the casing of the cou-pl-inggor toa-sheathingof the couplingof similar material vfrom which the operatin ikl ob projects.

I claim as my invention;

1. Electrical coupling comprising ,a twoepart 4 casing, terminals for cable connection, and coupling contacts, wherein a rotary switch connected between one of the contacts and one of the terminals is formed by a contact bridge rigidly secured to a spindle which is slidable and guided in an operating member projecting outside the easing, the said spindle and member being connected together by a spring for transmitting an axial pressure in the rest positions of the switch and a substantial torque for the quick contact making and breaking action, the operating member being rotatably supported. by a projection of the casing slitting into a circular groove of the said member to exert theaxial contact pressure via the spring Y and slidable sp ndle.

2. Electrical coupling comprisingca casing of ztorpedo shape divided in an. axial plane, a cable entry hole atone end of the torpedo shaped casing, a terminal for cable connection formin a unitary structure with one coupling contact, a rotary switch connected between the other terminal vfor cable connection and the other "coupling contact consisting of a contaet bridge rigidly fixed to a spindle which is slidableandguided mamas bore of an operating memberprojecting .outside'the casing, a spring connecting the said spindle .and operating member .to transmit an axial pressure in thelrest positions of the switch, and a substantial torque sutficing topro- ERVJSN -MEST.IFI Z.

, REFERENCES CITED The following references are of record in the .file of patent:

STATES PATENTS Name Date 445,362 Bengmann Jan. 27,1891 480,948 Hutchinson Aug. 16, 1892 1 ,597,437 De Reamer 24, 1,926 1,98%,925 Peterson Jan. 8 21.935 2,941,414

Johnson May 19,1936 

